Head flowing fluid lift



16, 1932- 1 .1. PENROD 1,845,181

" HEAD FLUWING FLUID LIFT 9 Filed May 26, 1927 3 Sheets-Sheet l KIIJI'I/ll VIII- VIII I gwuenl oz Feb. 16, 1932. 5 J. 5 100 1,845,181

HEAD FLOWING FLUID LIFT Filed May 26, 1927 I5 Sheets-Sheet 2 gwventozJafln 7%1200,

Patented Feb. 16, 1932 narrate stares PATENT orrics JOHN PENROD, OFOKMULGIlElI-l, OKLAHOMA, ASSIGNCR OF ONE-HALF T ROBERT D.

THOMPSON, or OKMULGEE, OKLAHOMA 7 HEAD FLOWING FLUID LIFT- a ucauonai eMay 26,1927. Serial No. 194,370.;

This invention relates to fluid lifts of the type whlch employcompressed a r. or, gas as a lifting medium.

Briefly. stated an important object of the invention is to provide afluid lift for wells having a novel form of valve adapted tobecontrolled by the hydrostatic pressure to allow the lifting medium, suchas compressed air or gas, to assume lifting relation tothe column offluid at the intervals when the compressed air or gas may be mostadvantageousiy employed, this feature of the nvention being calculatedto flow the well by heads and to conserve the supply of lifting medium.Another and equally important ObJGCt of the invention is to provide afluid lift embodying an air or gas actuated swab having means tominimize the mingling of the products of the well with the liftingmedium, such as compressed air or gas, the improved swab also havingmeans whereby the paraffin which attaches itself to the wall of thetubing is removed each time the well is flowed.

Another object is to provide a controlvalve for a fluid lift havingautomatic means by.

which the movement of the same to an extreme position in response topressure variatio-ns is delayed slightly to allow suflicient pressure tobe built up to cause the valve to move to an extreme position with thesuddenuefs desired to bring about the rapid opening and closing of theseparate port's by which the oil and the lifting medium enter. Theinvention forming the subject of the '35 application also contemplatesthe admission of native well fluid to the space immediately being inposition toadmit a lifting medium such as compressed air or gas,

Figure 2 is a fragmentary vertical sec- Figure 4 is a vertical sectionalview througha modification of the invention, the same being in positionto admit air or gas as the case may be, r.

Figure 5 is'asectional view through the pump in position to admit oil orother products of the well, I

Figure 6 is a perspectiveof a scraping element embodied in theinvention.

In the drawings the numeral 5 designates a tubing positioned within acasing 6 and having connection with the improved fluid lift by Wayof acoupling 7.

Figure 1 clearly illustrates that the cou-- pling has connection with ashell or casing 8 and a cylinder 9, the members 8 and 9be ing positionedone within the other and in spaced relation to define an annular chamber11 for the inflow of oil or other products of the well. At this point itmight be stated that the cylinder 9 is providednear the upperend thereofwith'a suitable number of ports 10 communicating with the afore saidchamber 11 and controlled by the upper section 12 of the piston valvefully illustrated in FigureB; When the upper section 12 is in itslowermost position as suggested in Figure 1 the ports 10' are closed toprevent the admission of oil from the chamberll to the tubing by way ofthe ports 10 and 3 L From the upper portion of the cylinder '9 The uppersection 12 of the piston valve is connected to the lower section 18 by atubular conduit 20 which extends above the piston section 12 anddischarges the com- 5 pressed air or gas in lifting proximity to theswab.

Figure 1 clearly illustrates that the piston section 18 is provided witha transverse'port 22 communicating with the tubular conduit 20 andadapted for registration with ports or passages 24 having constantcommunication with the space between the tubing and the casing.Therefore it is believed to be clear that when the piston section 18 isin its lower position as suggested in Figures 1 and 1a the liftingmedium, such as com pressed air or gas, may be allowed to enter thetubing from the casing. On the other hand when the piston section 18 isin the elevated position illustrated in Figure 2 the admission ofcompressed air or gas to the tubing is cut off.

As suggested in Figure 1 the inlet conduit or member 25 by'which oil orother products of the well is supplied to the annular chamber 11' isprovided with a packer 26 of conventional or other design. It isbelieved to be obvious that when the improved fluid lift is installed inthe well the packer will establish a fluid tight connection between thecasing and the member 25 so that the compressed air or gas supplied tothe space between the tubing and the casing will be prevented fromexercising a restraining influence on the oil or the like seeking toenter the pump. In other words. the packer 26 sets up an effectivebarrier between the compressed air and the producing stratum.

The piston valve is urged to the oil inlet position illustrated inFigure 2 by the air compressed, within the chamber 30 in the lowerportionof the cylinder 9. Figure 1 clearly illustrates that the lowerend of the piston section 18 is exposed to air compressed within thechamber 30 so that when the hydrostatic pressure on the upper end of thepiston section 18 is relieved to the required point the piston is movedupwardly to air excluding and oil inlet position.

In carrying out the invention a suitable valve 31 may be associated withthe chamber 30 by which air under pressure may be admitted to thechamber 30. A cap 32 may be of air from the chamber and to prevent thesupply of additional air or other fluid in case the pressure is greaterexteriorly of the charm ber than interiorly thereof.

A relief valve 33 may be employed to relieve excessive pressure withinthe chamber 30 as a result of leakage of the lifting me.- dium, such ascompressed air or gas, into the chamber 30. The building up of anexcessive pressure in the chamber 30 would defeat the purpose oftheinvention as it would preextended over the valve 81 to avoid leakagevent the movement of the valve section 18 to air or gas inlet positionunder the load of a predetermined volume of fluid in the tubing.

Attention is invited to Figure 1 which illustrates that the pistonsection 12 is provided with a suitable number of longitudinal ports 34by which the weight of the column of fluid accumulated within the tubingmay act on the upper end of the piston section 18 to urge the pistonsection 18 downwardly against the influence of the air compressed withinthe chamber 30.

During the accumulation of oil in the tubing the piston valve is held inan oil inlet position and in air or gas. excluding position by anelongated dog 40 having a stem or shank 41 positioned within a tubularcarrier 42 and encircled by a spring 43. The spring 43 is confinedbetween the inwardly flanged upper end of the tubular carrier 42 and anut 44 adjustable on the lower portionflof the stem. It is important tonote that when the piston valve is in the elevated positionillustratedin Figure 2 the rear or lower end of the dog rests upon the annularattaching portion of a sleeve 48, and the downward movement of the valveto air inlet and oil excluding position under the weight of the tubingfluid is resisted and delayed. The shoulder or lower end of the dog 40is urged laterally into seating engagement with the sleeve 48 by a bowedspring 53 confined between the dog 40 and the fluid conduit 20.

The ports 34 provide a means whereby the' pressure of the fluidaccumulated in the tubing is borne by the section 18 and when thepressure exceeds a predetermined value the section 18 will movedownwardly and carry with it the section 12. When the section 12 is thusmoved downwardly a lug or cam 50 carried by the same will be engagedwith the beveled upper portion of the dog 40 whereby the dog is movedlaterally out of seating engagement with the sleeve 48.

In summarizing the foregoing arrangement it is pointed out that the dog40 will transmit the entire weight of the column of accumulating fluidin the tubing until the weight of this fluid overcomes the resistance ofthe spring 43 at which period in the operation of the invention thesection 12 is moved downwardly to release the dog 40 from seatingengagement with the sleeve 48.

When the dog 40 is thus released the descent of the piston valve isresisted only by the air compressed within the chamber 30, but this willbe very much less than sufficient to hold the piston in anelevated'position so that the piston is moved downwardly 1 a springcatch 56 by which the return of the piston to oil inlet positionisdelayed until the pressure within the tubing is substantially belowthe pressure within the chamber 30. The dog 55 which is carried by thepiston will remain in locking engagement with the spring fastener 56-until the tubing pressure has dropped substantially by reason of themovement of the oil.

It is important to observe that. as a portion.

of the column of fluid is discharged from the tubing the compressed airor gas is employed eXpansively to accelerate the flow of the fluid. Whenthe compressed air or gas thus expands a substantial drop in tubingpressure will occur sothat the piston valve is moved to oil inletposition prior to the complete discharge of-the column of fluid above.Therefore, additional oil or gas may enter from the producing stratum byway of the ports 10 to assist theexpanding lifting medium in completingthe discharge of the column of fluid above the swab. In explaining thisit'is pointed out that during the admission of compressed air or gas forhead flowing the well the natural pressure of the producing stratum willbe increased toa point where the oil will be supplied to the tubing byway of the ports in sufiicient volume and with sufficient force toaccelerate the movement of the column of oil above. This also-quickenseach cycle so that the natural pressure of the well actively cooperateswith the artificially compressed air or gas in flowing the well.

Of course during the admission of the lifting medium by way of the ports22 and 24 the supply of oil to the tubing is positively prevented.Therefore, the possibility of cutting the oil by mixing air or gas withit is minimized. As will be described later the mixing of the lifting.medium with the oil accumulated in the tubing is further minimized bythe employment of the swab 14. I

The piston valve section 18 is provided with sets of rings or cups 58,59 and 60 ar-J ranged in spaced relation and adapted to be positioned atopposite sides of the inlet ports 24 to avoid leakage of both oil andcom-* pressed air or gas. More specifically the sets of rings or cups 58and 59 are positioned at opposite sides of the inlet ports 24 when thevalve section 18 is in air inlet position. \Vhen the valve is in oilinlet. position the rings 59 of the valve section 18 its-chambered toreceive the depending sleeve 48 to define a trap, the lower portion ofwhich is supplied with compressed air or gas by ports 7 0 so that beredupper end of the section 18 gas will accumulate between the sleeve andthe cylinder 9 so that sand laden oil is prevented from working its wayinto destructive contact with the opposed surfaces of the section 18 andthe cylinder. V It will be seen that the attaching portion of the gastrapping sleeve 40 not only functions as such, but as a stop to limitupward movement of the piston valve under the influence of the. airwithin the chamber 30,

The swab 14 is in the nature of a rubber or metal body having atransverse wall or support 84 ported as shown at 90 for the entrance ofoil or other products or the well into the tubing. Normally the closureplate 85 beneath the port -is spaced from the port by coil springs 88whereby oil or the like may freely flow upwardly through the swab. Theclosure 85 is suspended from stem or hangers 86 against which coilsprings 88 are engaged. It is the office of the springs '88 to urge theclosure 85 to open position:to allow of' the free passage of oil throughthe port 90. However, when the valve section 18 is moved to air or gasinlet position the inrushing air or gas will by reason of the greatervolume and pressure thereof promptly move the closure plate 85 to theposition illustrated in Figure -1 Whereby the port 90 is closed andtheswab moved upwardly.

That oil or other product of the well which flows through the swab isdischarged from the swab by way of a port 91 with which a flap valve921s associated. It will be seen that the flap valve 92 will relieve theclosure plate 85 of the weight of the column of fluid above when theswab is being elevated. In

other words, the column of fluid being elevated will have the effect ofholding the flap valve 92 in closed position while the lifting medium,such as compressed air or gas, discharged under the swab will hold theclosure plate 85 in closed position. This double valve arrangementpermits the swab to move upwardly without the leakage of air or oilthrough the swab.

Figure 1 illustrates that the diameter of.

the swabis slightly less than the diameter of the tubingand that theupper portion of the tubing is provided with an annular scraper 96adapted to have scraping contact with the walls of the tubing during theflowing of the. well. It will be seen that the scraping ring 96 isradially out to provide a number of separate scraping members which haveefiective contact with the wall of the tubing to remove paraflintherefrom. The upper end of the swab defines somewhat of a shoulder bywhich the scraper 96 is held in operative position during the ascent ofthe swab. However, on the descent of the ring 96 the inherentflexibility of the scraper will permit the edge portion of the scraperto bend upwardly so that the swab will not be seriously retarded in itsdescent. In other words, the action of the scraper is strictly one-way.

The descent of the swab is cushioned by the column of air or oil below.6 In explaining this it is pointed out that the column of air beneaththe swab will move the plate 85 to closed position should the swabdescend too rapidly and the swab will be slackened in its speed; Whenthe swab drops to the level of the column of oil accumulated in thetubing during the previous head flowing of the well its descent will befurther cushioned whereby destructive contact of the swab with theconduit is avoided.

The limited space between the swab and the tubing and the pressurebehind the lifting medium will prevent the leakage of oil about the swabduring the elevation thereof whereby mingling of the oil and thelifting, medium is minimized. By thus maintaining the oil separate fromthe lifting medium cutting or emulsifying of the oil is greatly reduced.Also by maintaining the liftingmedium separate from the column of oilbeing elevated a reduction in the gravity of the oil isavoided.

It is intended to have superposed outlets at the upper portion of thetubing spaced a greater distance than the length of the swab so thatwhen the swab passes the lower outlet a portion of the lifting mediummay be discharged to allow of the free descent of the swab.

n 'In the form of invention illustrated in Figures 4 and 5 the shell 100encloses a cylinder 101 within which a piston valve 102 operates. Tncarrying out this form of the invention the piston valve is providedwith a transverse port 108 adapted for communication with inlet ports orpassages 104. Of course, the passages 104 are adapted to establishcommunication between the interior of the well casing and the transverseport 103 whenthe piston valve is in open position. Figure 5 clearlyillustrates that the piston 102 is provided with a port 106communicating with the port 103 and the lower portion of the cylinder101. Air admitted to the lower portion of the cylinder byway of the port106 enters the shell 100 by way of ports 108 and flows upwardly intolifting relation to the column of oil above.

The upper portion of the cylinder 101 contains compressed air by whichthe piston 102 is constantly urged to the closed position illustrated inFigure 5.

- When the piston 102 is in closed position the bill on the lower end ofthe elongated dog 110 is engaged with a shoulder 111 on a member'1l2..The elongated dog 110 is extended through a barrel 114 having aninternal cam 116 adapted to engage a cam or beveled surface on theadjacent portion of the elongated dog 110 so that when the tubingpressure acting on the under side of the piston 102 exceeds apredetermined point the locking dog 110 will be moved laterally out ofengagement with the shoulder 111. lNhen the locking dog 110 is thusreleased from engagement with the shoulder 111 the tubing pressure isallowed to move the piston valve 102 to open position with speed wherebycompressed air or gas may flow in through the ports 104, 103, 106 and108 in suii'icient volume and with sulficient velocity to effectivelylift the oil.

Figure 5 illustrates that a spring 115 is mounted on the upper portionof the dog 110 and is held thereon by an adjustable nut 117 by which thepressure under which the spring is compressed may be varied; In use thenut is adjusted on the elongated dog 110 to cause the spring 115 toyield under a given-tubing pressure. The initial movement of the piston102 results in the engagement of the coacting cams or shoulders on thebarrel 114 and the dog 110 so that the bill of the dog is removed fromengagement with the shoulder 111. It will be seen thatthe dog 110 isurged laterally in the direction of the member 112 by a bowed spring118. Of course when the shoulder 116 is engaged with the opposedshoulder on the dog 110 the pressure of the bowed spring 118 will beovercome with the obvious result that the bill of the dog will bereleased from engagement with the shoulder 111.

When the piston 102 is thus moved to open position a second dog 120carried by the upper end thereof is engaged with the laterally pro- 1jecting terminal portion of a spring catch 124. The spring catch 124 iscarried by the upper end of the cylinder 101 and when engaged with theshoulder of the dog 120 will delay the return of the piston 102 toclosed position under the influence of the air in the air chamber.

Oil is admitted to the lower portion of the cylinder" 110 through aone-way valve 130, the ball of which is firmly held in seated positionby the lifting medium during its flow through the lower portion of thecylinder.

Preparatory to the installation of the improved fiuid lift into a wellthe tension of the spring43 is adjusted by the nut 44 to permit of therelease of the piston valve under a given tubing pressure. By this meansthe volume of oil to be elevated at each flowing operation may beregulated. The chamber is supplied with air which exerts a pressuresomewhat less than the pressureof the spring 41 so that whenthe dog 40is released the piston valve may promptly move to air inlet position.

When the improved pump is installed in the well oil is allowed toaccumulate in the tubing until the weight of this oil overcomes thespring 43 and causes the lug 50to trip the dog 40 whereupon the pistonvalve is moved to open position. Air or gas under pressure now entersand is discharged in the lower portion of the tubing and against theclosure plate 85 so that the closure plate is caused to move upwardly tocut off the port 90. The swab and the column of oil above now ascend,during which time the scraping ring 96 removes the paraifin or asubstantial portion of it from the tubing.

As a portion of the column of fluid leaves the tubing the air isexpanded'to accelerate the movement of the remaining oil in the tubing.When the air is thus expanded the tubing pressure will drop so that thepiston valve is moved to air excluding and oil inlet position whereuponthe built up natural pressure of the well will cause the oil to enterthe tubing and aid in the completion of the flowing operation. Thecompletion of one flowing operation is marked by the descent of the swabto theposition illustrated in Figure 1 and when theoil reaches apredetermined height the tubing the pressureof the same will again movethe piston valve to oil excluding and air inlet position whereupon thewell is flowed again.

Having thus described the invention, what is claimed is: v

1. In a fluid lift for oil wells, a casing-having separate passages foroil and an oil lifting medium, a piston having means separatelycontrolling said passages to close the oil passage when the passage forthe oil liftingmedium is open, and meansto hold said valve in positionto admit oil and to exclude the oil lifting medium until the weight ofthe column of oil exceeds a predetermined value.

2. In a fluid lift for oil wells, a casinghaving passages for oil and anoil lifting medium, a piston having means separately c'ontrolling saidpassages to close the oil passage when the passage for the oil liftingmedium is open, a member to hold said valve in position to admit oil andto exclude the oil liftingmedium until the weight of the column of oilexceeds a predetermined value, and a releasing device for said member.

3. In a fluid lift for wells, a tubing, a cylinder having means wherebythe same may be connected to the tubing and having separateinl'etsforoil and an oil lifting medium, a. piston in said cylinder andadapted to separately close said inlets toexclude the oil lifting mediumduring the admission of oil, a dog holding the valve in a predeterminedposition, and a tripping member adapted to engage said dog to releasethe same.

7 4. In" a fluid lift, a tubing for the passage of oil, a cylinderhaving means whereby the same may be incorporated in the tubing andbeing provided with separate inlets for the admission of oil and an oillifting medium, a piston having spaced sections controlling said inletsand positioned to exclude an oil lifting medium during the flow of oilthrough the oil inlet, there being yieldable means associated with saidpiston to support a column of fluid of a predetermined height in thetubing, and means urging said piston-to oil inlet position.

5. In a fluid lift for wells, a cylinder hav-- inder having meanswhereby the same may be connected to the tubing and being provided withpassages for oil and an oil lifting medium, a valve controlling saidpassages and being exposed to hydrostatic pressure,a spring pressed dogholding said valve in oil inlet position against'a predeterminedhydrostatic pressure, and separate means urging said valve to oil inletposition.

7 In a fluid lift for wells, a'cylinder hav ingpassages for oil and anoil lifting medium, a valvewithin said cylinder and havinga chamberedportion, a sleeve connected to said cylinder and extending into thechambered portion of said valve to cooperate therewith in the formationof a gas trap in protecting relation to one end of the valve, said valvehaving means controlling said passages. V

8'. In a fluid lift for wells, a cylinder having passages for oil and anoil lifting medium,

a passage controlling valve within said cylinder andhavinga chamberedportion, a sleeve connected to said cylinder and extending into thechambered portion of said valve to cooperate therewith in the formationof' a gas trap. in protecting relation to one end of the valve, and aspring pressed dog associated with said valve and having means to engagesaid sleeve to hold the valve in a fixed position against apredetermined hydrostatic pressure.

9. In a swab for use in fluid lifts of the type described a freelymovable body having a passage, a valve associated with said passage andhaving a spring'urging the same to open position, and a second valveassociated with said passage and movable to closed posi berhavingseparate passages for the products of a well and a lifting medium, avalve having means separately controlling said passages, a springpressed dog carried by said valve, a seating device for said dog andadapted to hold the dog in a set position under'a predeterminedhydrostatic pressure on said valve, and a releasing device for saiddog... I

11. In a fluid lift for-wells, a cylinder having separate passages forthe products of a well and a fluid lifting medium, a piston valve insaid cylinder and having sections separately controlling said passages,said piston valvebeing provided with means connecting said sections, asleeve between said sections and cooperating with one of the sections inthe formation of a trap, and means to hold said piston valve inposition, to admit the products of the, well to-said cylinder,

12. In a fluid lift for wells, a cylinder having separate passages for alifting medium and the products of a well, a valve associated with saidcylinder and having a pair of spaced sections separately controllingsaid passages, a fluid conduit rigidly connecting said sections, asleeve carried by said cylinder at a point between said sectionsvandcooperating with one of the sections in the formation of a trap, and adog carried by one of said sections and adapted to engage said sleeve tohold the valve in a set position under a predetermined hydrostaticpressure.

13. A swab for use in wells comprising a freely movable body having apassageextending entirely therethrough, a one-way valve controlling saidpassage, and a second oneway valve controlling the passage, said valvesbeing movable in opposite directionto open position.

14. A swab for use in wells comprising a freely movable body havingseparate ports, a one-way valve controlling one of saidports, a secondone-way valve control ing the other port, and a paraflin scraping devicecarried bysaid body, said valves being movable in opposite directions toopen positions. 7

15. A swab for use in a well tubing comprising a freely movable body,and a ring extending beyondthe body and having an edge portion adaptedto remove paraffin from the Wall of the well tubing, and being movablewith respect to the body.

16. In an apparatus for recovering liquid from wells, a fluid conductorin the well and having a passage for a pressure fluid, a passagecontrolling valve substantially below the level to which the native wellliquid rises naturally and urged to open position by the pressure ofsuch liquid above the same, and a casing having a substantially isolatedbody of eXpansible gas urging the valve to closed position and beingyieldable to a superior pressure of the native well liquid above theValve. r

7 17. In an apparatus for recovering liquid from wells, a fluidconductor in the well and having a passage for a pressure fluid,apassage controlling valve substantially below the level to which thenative well liquid rises naturally and urged to open position by thepressure of such liquid above the same, a casing having a substantiallyisolated. expansible body of. gas urging the valve to closed positionand being yieldable to a superior pressure of the native well liquidabove the valve, and a restraining means holding the valve in open andclosed positions and yieldable to a predetermined pressure.

18. In an apparatus for recovering liquid from wells, a fluid conductorin the well and having a passage for a pressure fluid, a passagecontrolling valve substantially belowthe level to which the native wellliquid rises naturally andurged to open position by the pressure of suchliquid above the same,- a casing having a substantially isolated body ofinitially compressed gas urging the valve to closed position andbeing-yieldable to a superior pressure ofthe native well liquid abovethe same, and means cooperating with said body of gas to hold the valvein closed position against a predetermined pressure of the nativewellliquid above the same. a

19. In an apparatus for recoveringliquid from wells, a fluid conductorin the well and havin a passage for a pressure fluid, a pas sagecontrolling valve substantially below the level to which the native wellliquid rises naturally and urged to open position by the pressure ofsuch liquid above the same, a casing having a substantially isolatedbody of initially compressed gas at one end of said Valve and urging thevalve to closed position, said body of gas being yieldable to a superiorpressure of the native well liquid above the same, and a restraining.device releasably holding the valve in openposition against apredetermined pressure of said gas.

20. In an apparatus for recovering liquid from wells, a conductor in thewell and having a passage for a pressure fluid, a passage .controlhngvalve in the well ata point substantiallybelow theheight to which thenative well liquid rises, said valve being subject to and urged to openposition by the pressure of thenative well liquid, and a member having,an initially compressed elastic body of gas urging the valve to closedposition against the pressure of the native well liquid above the valveand being yieldable to a superior pressure ofsuch liquid.v

21. In an apparatus for recovering liquid from wells, a conductor in thewell and having a passage for a pressure fluid, a passage controllingvalve at'a point in the well substantially below the height to which theWell liquid rises naturally, said valve being subjectto and urged toopen position by the pressure of such liquid, a member having an elasticbody of gas urging the valve to closed position against the pressure ofthe native well liquid above the valve and being yieldable to a superiorpressure of such liquid, and releasable restraining devices securingsaid valve in open and closed positions.

22. In an apparatus for recovering liquid from wells, a conductor in thewell and having a passage for a pressure fluid, a passage controllingvalve in the well at a point substantially below the height to which thenative well liquid rises naturally, said valve being subject to andurged to open position by the pressure of such liquid, and a memberhaving an initially compressed elastic body urging the valve to closedposition against the pressure of the native well liquid above the valveand being yieldable to a superior pressure of such liquid.

23. In an apparatus for recovering liquid from wells, a conductor in thewell and having a passage for a pressure fluid, a passage controllingvalve in the well at a point sub stantially below the height to whichthe native well liquid rises naturally, said valve being subject to andurged to open position by the pressure of such liquid, and a memberhaving an initially compressed substantially isolated elastic body ofgas urging the valve to closed position against the pressure of thenative well liquid above the valve and being yieldable to a superiorpressure of such liquid.

24:. In a gas-lift liquid pump for wells, two vertical conduits, a valvefor controlling the passage of fluid from one conduit into the other, amember having resilient means exerting force on the valve to close thevalve when a predetermined diflerential of pressure between the interiorand the exterior of the member is reached and means excluding the nativewell liquid from one of thevertical conduits.

25. In a gas-lift liquid pump, two vertical conduits, a valve forcontrolling the passage of fluid from one conduit into the other, and amember having an isolated body of gas exerting force on the valvetending to close the valve when a predetermined differential of pressurebetween the interior and the exterior of the member is reached.

26. In a gas-lift pump for wells, an inlet conduit, an outlet conduit, avalve for controlling the passage of fluid from one conduit into theother, a member having means therein exerting force on the valve toclose it when a predetermined diflerential of pressure is reachedbetween the interior and the exterior of the member, and means excludingthe native well liquid from the inlet conduit.

27. In a gas-lift pump for wells, an inlet conduit, an outlet conduit, avalve for controlling the passage of fluid from one conduit into theother, a member having an expansible body of gas located in the well ata point substantially below the level to which the native well liquidrises naturally and exerting force on the valve to close it when apredetermined differential of pressure-is reached between the interiorand the exterior of the member.

28. In a swab for use in well tubings, a freely movable cylindrical bodyadapted for vertical reciprocation in a well tubing, and a membercarried by the body and projecting beyond the periphery thereof forscraping. engagement with the wall of the well tubing.

29. In a swab for use in well tubings, a freely movable cylindrical bodyadapted for vertical reciprocation in a well tubing, and a membercarried by the body and projecting beyond the periphery thereof forscraping engagement with the wall of the well tubing and being free toyield during the descent of the body.

30. In a swab for use in Well tubings, a freely movable cylindrical bodyadapted for vertical reciprocation in a well tubing, and a membercarried by the body and projecting beyondthe periphery thereof forscraping engagement with the wall of the well tubing and being free toyield during the descent of the body, said body being provided withmeans bracing the member during the ascent of the same.

31. In a swab for use in well tubings, a freely movable cylindrical bodyadapted for vertical reciprocation in a well tubing and being providedwith a fluid passage, a valve controlling said passage, and a scrapingmember'carried by the body and projecting beyond the periphery thereoffor scraping engagement with the wall of the tubing, said scrapingmember being yieldable in one direction.

In testimony whereof I aflix my signature.

JOHN PENROD.

